Update of an earlier June 24th, 2014 post:
The Moon's orbit is tilted by approximately five degrees compared to the Earth-Sun plane. The net effect of this is that the strength of Lunar-tides near the mid-latitudes of the Earth's surface varies in strength over a cycle of 18.6 years. This 18.6-year Draconic cycle is also clearly evident in the small changes that take place in the rate of rotation of the Earth.
The above graph clearly shows that Victoria experienced increased annual precipitation around 1917, (1936), 1955, 1973-74, 1992, and 2010-11. These years are separated by ~ 18.6 years and occur at times which correspond to peaks in the strength of the Draconic tides.
Confirmation of the 18.6-year periodicity in the positive annual rainfall anomalies is provided by the auto-correlation of the Victorian annual rainfall anomalies between 1900 and 2017.
Note the effect of the short-term 4-year alignment of the lunar tidal cycles with seasons superimposed upon the 18.6-year cycle.
Why is the Australian BOM ignoring this obvious piece of evidence that connects the annual rainfall in Victoria to long-term changes in the Lunar Tides?
Will they be ready for the next period of increased precipitation around 2029?
Please refer to the following papers for a possible explanation of this phenomenon:
Wilson, I.R.G., Lunar Tides and the Long-Term Variation
of the Peak Latitude Anomaly of the Summer Sub-Tropical
High-Pressure Ridge over Eastern Australia
The Open Atmospheric Science Journal, 2012, 6, 49-60
Southern Hemisphere, The Open Atmospheric Science Journal,
2013, 7, 51-76